Analysis of the bending and failure of fiber metal laminates based on glass and carbon fibers

Abstract

The purpose of this paper is to investigate the mechanisms of cracking and failure in fiber metal laminates (FMLs) subjected to 3-point bending. Two types of laminates, based on the glass/epoxy and carbon/epoxy composites, were selected for the study. The paper presents the failures of matrix and fibers as well as the effects of different thicknesses of metal layers on the tested laminates. The mechanisms of failure observed for the two tested types of fibers with uniform thickness of aluminum sheets seem similar. The results demonstrate that the tested laminates exhibit the following failure modes: fiber breakage, matrix cracking, fiber/matrix debonding, delamination, and anodic layer failure. Given the behavior of aluminum under the compressive and tensile stresses, the aluminum layer acts as a barrier preventing FML failure during bending. In addition to aluminum layer thickness, the fiber type and composite layer directions are also important factors to be considered.